Nozzles are frequently used for spraying fluids in the form of individual liquid droplets such as in jet printing with liquid ink. In such systems it is usually undesirable for the fluid that is being sprayed to wet the nozzle surfaces. Such nozzle wetting in ink jet printers, for example, reduces print quality by permitting the generation of spurious droplet called satellites, in addition to the main droplet of interest. In addition, if the wetting is serious enough it is even possible that the liquid will no longer exit the nozzle as drops at all.
A conventional solution to the nozzle wetting is to treat the outer surface of the nozzle with an anti-wetting compound such as a long chain fluorosilane compound. Such coatings are usually applied as thin coats or even monolayers so as not to greatly alter the nozzle characteristics. Unfortunately, such a coating even though on the outer surface of the nozzle is only a temporary solution to nozzle wetting, since the integrity of the anti-wetting compound bond to the nozzle is often sensitive to the constituents of the fluid being sprayed, such as the dyes or the solvents used in many conventional inks, and hence the anti-wetting compound is soon washed away.